Question about moisture meters

[polkadottie55]

I have read on this forum that you should bring wood inside and let it get warm then take it outside and split and measure the moisture content. I don't understand why this is. Also I have measured the moisture in wood that I split today where you can obviously see the difference between dry wood and wood that has been soaked with moisture. The meter reads 21% in the dry area and 21 or 22% in the obviously wet area. However, even in wood that has been seasoned for 2 years or more, I still get moisture readings of 23%. Does wood absorb moisture from the air enough to raise the internal moisture of a wood chunk?

 

[begreen]

That's a very small piece of wood. Try on a full sized split. Note that .4% difference is nothing. It could vary that much based on how deep the pins are seated into the wood.

 

[stoveliker]

The reason for the temperature is that the moisture meter measured electric resistance, which is mostly determined by the water content. The resistivity of water (with ions dissolved in it) depends on temperature so the calibration of the meter is done at a specific temperature.
Now if the wood is 55 F instead of 70 F it won't be the end of the world.
But if the water in the wood is near freezing, the difference will be large. The meter will see a high resistance and tell you a low moisture content, but that would be wrong.

If the wood in the two years is regularly exposed to water, and depending on the openness of the grain, it will not dry as much as when it's kept out of the rain

 

[Ctwoodtick]

Wood species might make for the difference partly. Oak will take far longer to dry than pine for example.
Do you top cover your wood? Note that you should not fully cover your wood- just the top to keep rain off while allowing for moisture to dissipate.

 

[polkadottie55]

The reason for the temperature is that the moisture meter measured electric resistance, which is mostly determined by the water content. The resistivity of water (with ions dissolved in it) depends on temperature so the calibration of the meter is done at a specific temperature.
Now if the wood is 55 F instead of 70 F it won't be the end of the world.
But if the water in the wood is near freezing, the difference will be large. The meter will see a high resistance and tell you a low moisture content, but that would be wrong.

If the wood in the two years is regularly exposed to water, and depending on the openness of the grain, it will not dry as much as when it's kept out of the rain

It is kept out of rain with a roof but no sides so it is exposed to air and we have had a month of lots of rain

 

[Ctwoodtick]

It is kept out of rain with a roof but no sides so it is exposed to air and we have had a month of lots of rain

Sounds like you’re doing all you can do. Wood in the low 20’s is IMO “good enough”. It will be drier than that with some dryer spring and summer weather.

 

[polkadottie55]

My cad Heritage says below 20 percent to protect the catalytic combustor?

 

[polkadottie55]

That's a very small piece of wood. Try on a full sized split. Note that .4% difference is nothing. It could vary that much based on how deep the pins are seated into the wood.

I would have expected a large difference between the dry area and the wet area?

 

[Ctwoodtick]

My cad Heritage says below 20 percent to protect the catalytic combustor?

Ok I wasn’t think of cat stove. I’m guessing it’s a matter of degree. Moisture of 40 percent is more an issue than 22 percent.

 

[Murray01]

I would have expected a large difference between the dry area and the wet area?

With the pins stuck into the wood you are measuring water on a molecular level, I think. If the wet area is from rain then you’re looking at surface moisture. By laying your pins across, not penetrating the wet wood I would think you would get a higher moisture content.